Big game hunting is controversial. Some people object to all hunting, while others take exception to hunting for sport. Last month, there was an uproar on the Internet when Outdoor Channel TV personality Melissa Bachman tweeted a photo of herself and a dead lion in South Africa. More than 400,000 people signed a petition calling for South Africa to ban Bachman from returning to the country.

What she had done was legal, however. Some African nations, including South Africa, sell rights to hunters to hunt and kill animals that many of us consider treasures. The trophy fee for a lion in South Africa in 2014 is set at $22,000. A zebra in Tanzania runs $1,500. An elephant in Zimbabwe is $15,000. There is decent logic behind the practice: The loss of a few animals pays for conservation efforts aimed at saving the rest. Alexander N. Songorwa, director of wildlife for the Tanzanian Ministry of Natural Resources and Tourism, in arguing for continued lion hunting earlier this year in the New York Times, noted that in his country:

The money helps support 26 game reserves and a growing number of wildlife management areas owned and operated by local communities as well as the building of roads, schools, hospitals and other infrastructure — all of which are important as Tanzania continues to develop as a peaceful and thriving democracy.

Sustainable trophy hunting is possible. Trophy fees facilitated the recovery of bontebok, black wildebeest and cape mountain zebra in South Africa, for example. But achieving such sustainability is difficult. Many nations lack good data on current population levels of wildlife, so figuring out how many animals can be killed without causing a decline in the overall population is a challenge. In addition, there is added pressure to set quotas high to make as much money as possible.

The financial pressures are definitely a problem, but the lack of data need not be, say Charlie Edwards of Imperial College London and colleagues. The researchers developed an algorithm that replaces current population levels with a much easier count — the number of safari days required to kill a lion — to predict sustainable quotas. Their study was published December 16 in the Proceedings of the National Academy of Sciences.

A safari’s waiting time is a decent measure of the overall size of the lion population, the researchers found, even if it depends on a multitude of other factors, such as the skills of the trackers. But the formula works only if male lions older than age 6 are the ones killed. If females and younger males are removed from the population, the quota must be set lower because of their value in breeding and growing the population. So hunters’ penchant for killing large, old lions with iconic manes actually works in the big cats’ favor.

The researchers say that their method should help to maintain the lion population and would even work for other data-poor animal populations. But, personally, I remain unconvinced of the value of killing such beautiful creatures, especially if their deaths are for no other reason than sport (I have no problem with responsible hunting undertaken for sustenance).

And I also worry about how the rise in wildlife poaching in Africa might play into the sustainability problem. Demand for ivory has caused mass slaughters of elephants; 22,000 were killed in 2012 alone. Rhinoceros species are being driven into extinction as the animals are killed for their horns, which are used in jewelry and “medicine.” Even if trophy hunting is done at a sustainable level, is it just helping poachers drive species out of existence?

Ending trophy hunting presents its own challenges. On January 1, commercial hunting will become illegal in Botswana; the environment ministry says that trophy hunting isn’t compatible with their efforts to preserve the nation’s animal populations. This may seem to be a good thing for the local fauna, but there are concerns about the effects of larger animal populations on the environment. And if nothing is done to help local communities that are now dependent on hunting revenue, the ban could create incentives for poaching.